01数组

创建数组

<script type="text/javascript">
        var go = [];
        document.write(typeof(go)+"<br/>");
        console.log(typeof(go));
        var go1 = new Array(3);
        document.write(go1+"<br/>");
        console.log(go1);
        document.write(typeof(go1)+"<br/>");
        console.log(typeof(go1));
        var go2 = [45,454,87,{"nemra":56}];
        document.write(go2+"<br/>");
        console.log(go2);
        var go3 = new Array(48,598,15,"asdsd");
        document.write(go3+"<br/>");
        console.log(go3);
    </script>

image.png

数组遍历：

<script type="text/javascript">
        var go2 = [45,454,87,{"nemra":56}];
        for(var i=0;i<go2.length;i++){
            console.log(go2[i]);
        }
    </script>

image.png

数组栈方法：

1.push()
2.unshift()
3.pop()
4.shift()

push

<script type="text/javascript">
        var go = [45,454,87,{"nemra":56}];
        var x = go.push("color","red");
        console.log(go);
        console.log(x);
    </script>

image.png unshift()

<script type="text/javascript">
        var go = [45,454,87,{"nemra":56}];
        var x = go.unshift("color","red");
        console.log(go);
        console.log(x);
    </script>

image.png pop shift()

<script type="text/javascript">
        var go = [45,454,87,{"nemra":56}];
        var x = go.pop()
        console.log(go);
        console.log(x);
    </script>

pop()

<script type="text/javascript">
        var go = [45,454,87,{"nemra":56}];
        var x = go.shift()
        console.log(go);
        console.log(x);
    </script>

shift() join()

如果没有参数默认用逗号隔开！

<script type="text/javascript">
        var go = [45,454,87,56];
        var strs = go.join("-");
        console.log(strs);
    </script>

join() 颠倒排序方法

    <script type="text/javascript">
        var go = [45,454,87,56];
        go.reverse()
        console.log(go);
        
    </script>

排序
排序是第一个

var c = go.sort(function(a,b){return b-a});//降序排列
var c = go.sort(function(a,b){return a-b});//升序排列

    <script type="text/javascript">
        var go = [45,454,87,56];
//      var c = go.sort(function(a,b){return b-a});//降序排列
        var c = go.sort(function(a,b){return a-b});//升序排列
        console.log(c);
        
    </script>

concat()

<script type="text/javascript">
        var arr1=['a','b',"c"],
            arr2=["e","f","g"],
            arr3;
        arr3=arr1.concat(arr2);
        console.log(arr3);
        
    </script>

image.png image.png slice()

<script type="text/javascript">
        var arr1=['a','b',"c","d","e"];
        var newarr1 = arr1.slice(1,3);
        console.log(newarr1);
    </script>

前闭后开

面试题

var arr1=['a','b',"c","d","e"];
       arr2;
//arr2拷贝arr1 方法越多越好

给出答案，还未给完。

    <script type="text/javascript">
        var arr1=['a','b',"c","d","e"];
        var arr2;
        arr2=[];
//      arr2=arr1.concat(arr2);
        arr2=arr1.slice(0);
        console.log(arr2);
    </script>

splice()
splice()

<script type="text/javascript">
        var arr1=['a','b',"c","d","e"];
        var arr2=arr1.splice(2,2);
        console.log(arr1);
        console.log(arr2);
    </script>

image.png image.png

<script type="text/javascript">
        var arr1=['a','b',"c","d","e"];
        var arr2=arr1.splice(3,0,"m","n");
        console.log(arr1);
        console.log(arr2);
    </script>

image.png image.png

<script type="text/javascript">
        var arr1=['a','b',"c","d","e"];
        var arr2=arr1.splice(1,2,"m","n");
        console.log(arr1);
        console.log(arr2);
    </script>

image.png image.png image.png

<script type="text/javascript">
        var arr1=['a','b',"c","d","e"];
        var arr2=arr1.indexOf('c');
        console.log(arr1);
        console.log(arr2);
    </script>

image.png

String

学习目标 image.png

    <script type="text/javascript">
        var str='hello world';
//      var o = str[1]; //charAt()  
//      var o = str.charAt(1);
        var o = str.charCodeAt(1);
        console.log(o);
    </script>

image.png image.png lastIndexof() image.png image.png image.png
image.png
image.png
image.png

<script type="text/javascript">
        var youinput = prompt("亲输入登陆邮箱");
        function get_usr(youinput){
            s = youinput.lastIndexOf("@");
            var usr = youinput.slice(0,s);
            return usr;
        }
        function get_sever(youinput){
            var sever = youinput.slice(s);
            return sever;
        }
        var usr = get_usr(youinput);
        var sever = get_sever(youinput);
        document.write("邮件用户名为："+usr+"<br/>");
        document.write("邮件服务器为："+sever);
    </script>

image.png image.png

<script type="text/javascript">
        var str = "welcome-to-chengdu";
        //使用split将str转换为数组
        var arr=str.split("-");
        console.log(arr);
    </script>

image.png image.png image.png